Food Allergen Testing - Facts vs. Fiction (6)

Analysts all over the world need to ask themselves one essential question: Is my test result correct? In most cases, the answer is given by a reference method or a reference material, making it possible to evaluate the correctness of measurements.

Food allergen testing poses a special challenge in this context as there is no reference method and so-called “allergen reference materials” are not globally accepted. But why is it so difficult to produce such a material?

This sixth and final issue of our series sheds some light on the common misconception that allergen reference materials are available.

Although there are some materials on the market that claim to be an “allergen reference material”, none of them are really accepted as such. People often believe that this has mainly political reasons, but in fact, producing this kind of material in large quantities is a very difficult task and many aspects need to be considered.

The controversy about allergen references In other fields of food safety, producing reference materials requires high-end technology, but the procedures for doing so are well-established. If we take mycotoxins for example, we have one defined molecule, allowing accurate calculations of the final concentration. Unfortunately, with food allergens there is not just one specific molecule. An allergenic commodity consists of a mixture of different proteins. To date, several allergenic proteins have been identified, but the majority of them remain unknown. Furthermore, the protein pattern varies between different cultivars of the same species. And to make the situation even worse, proteins can change their conformations, which may lead to a change in their allergenic potential.

Allergen “reference materials” on the market Of course, it is possible and also common practice to produce mixtures of allergenic food commodities in certain matrices and label them as reference materials. But even if all calculations and handling steps are completed with the greatest of care, we never know if the material is really representative. Is the matrix a relevant one? How much difference is there to cultivars that are used in other parts of the world? Does the material mimic the same situation that allergic individuals face? Have altered protein conformations been considered? What about homogeneity, stability…?

So, should I forget about these materials? It must be remembered that these materials may not be real reference materials. They are not able to tell if a test result is correct or not. Nevertheless, if used with care and considering all known limitations, they can be very beneficial for regular checking test performance. The result should never be correlated with the result of an unknown sample, but it is a useful tool to confirm the consistency of test results. For example, they can be used to reveal handling errors or deficits of the test kit. Materials that are produced in-house using the matrix in question result in even more significant evaluations of test performance, and represent the best possible alternative we currently have until standardization bodies define specifications for actual reference materials.

This article was originally published in "International Food & Meat Topics", Volume 28 Number 6 (2017)